Diferenciação populacional em Drosophila sturtevanti (subgrupo sturtevanti, grupo saltans) avaliada por morfometria geométrica da asa e do edeago
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Data
2019-03-18
Autores
Segala, Luís Fernando
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Universidade Estadual Paulista (Unesp)
Resumo
A morfometria da asa e do edeago tem sido amplamente utilizada para estudar a evolução das espécies do gênero Drosophila pois são caracteres altamente sensíveis a variação genética e ambiental. No presente trabalho utilizamos esta técnica em um estudo populacional de Drosophila sturtevanti com ênfase em moscas procedentes de áreas de Mata Atlântica do Brasil e da Floresta Tropical Úmida da Costa Rica. Para isto utilizamos as asas e edeagos de machos destas populações e analisamos o nível de diferenciação quanto a estes marcadores discutindo sua associação com sua localização geográfica, a fitofisionomia do fragmento de mata, a umidade relativa média anual, a temperatura média anual e a área do fragmento de mata. Os resultados indicaram a existência de uma estruturação latitudinal tanto para o tamanho e a forma da asa como para a forma do edeago, além de correlação entre estas características e algumas variáveis ambientais. A diferenciação quanto à forma do edeago, entretanto, foi menos significativa que a diferenciação da forma e do tamanho da asa. A relação entre forma e tamanho das asas obtida foi divergente dos resultados encontrados para outras espécies de Drosophila, apresentando asas maiores e mais arredondadas nas populações da faixa latitudinal Sul 1 (PIR, AGU e RDI) e asas menores mais alongadas em uma população da faixa latitudinal Nordeste (CUR). As populações da Costa Rica (TIR e LSA) e as populações do Sul mostraram divergência significativa para os marcadores avaliados, entretanto, as populações da faixa latitudinal Sudeste (MAT, NGR, SDC, PIC e VIT) não apresentaram estruturas congruentes e foram melhor agrupadas por fitofisionomias. Os resultados apresentados refletem a diferenciação genética em curso nas populações de D. sturtevanti, sendo acentuada para as procedentes da América Central e as do Sul do Brasil, indicando a ocorrência de diferenciação populacional quanto aos marcadores estudados e que podem ser um reflexo da existência de novas espécies deste subgrupo, que já tinha sido sinalizado em estudos anteriores e também em estudos recentes do nosso laboratório com marcadores moleculares para estas mesmas populações.
Wing and aedeagus morphometry have been widely used to study the evolution of species of the genus Drosophila because they are highly sensitive characters to genetic and environmental variation. In this present research we use this technique in a populational study of Drosophila sturtevanti with emphasis on flies coming from Atlantic Forest areas of Brazil and the Tropical Rainforest of Costa Rica. For that we use the wings and aedeagus of males of these populations and we analyzed the level of differentiation regarding these markers discussing their association with its geographic location, the phytophysiognomy of the forest fragment, the average annual relative humidity, the annual average temperature and the area of the forest fragment. The results indicated the existence of a latitudinal structure for both the size and shape of the wing and the shape of the adeagus, besides the correlation between these characteristics and some environmental variables. The differentiation in the form of aedeagus, however, was less significant than the differentiation of the shape and size of the wing. The relation obtained between the shape and size of the wings was divergent from the results found for other Drosophila species, presenting bigger and more rounded wings in the populations of South 1 latitude (PIR, AGU and RDI) and smaller and elongated wings in a population from the Northeast latitude range (CUR). The populations of Costa Rica (TIR and LSA) and the South population showed significant divergence for the markets evaluated, however, the populations of the Southeast latitudinal range (MAT, NGR, SDC, PIC and VIT) did not present congruent structures and were better grouped by phytophysiognomies. The present results reflect the genetic differentiation in course in D. Sturtevanti populations, being accentuated for those coming from Central America and those from Southern Brazil, indicating the occurrence of an differentiation in relation to markers studied and that may reflect the existence of new species of this subgroup, which had already been signaled in previous studies and in recent studies of our laboratory with molecular markers for these same populations.
Wing and aedeagus morphometry have been widely used to study the evolution of species of the genus Drosophila because they are highly sensitive characters to genetic and environmental variation. In this present research we use this technique in a populational study of Drosophila sturtevanti with emphasis on flies coming from Atlantic Forest areas of Brazil and the Tropical Rainforest of Costa Rica. For that we use the wings and aedeagus of males of these populations and we analyzed the level of differentiation regarding these markers discussing their association with its geographic location, the phytophysiognomy of the forest fragment, the average annual relative humidity, the annual average temperature and the area of the forest fragment. The results indicated the existence of a latitudinal structure for both the size and shape of the wing and the shape of the adeagus, besides the correlation between these characteristics and some environmental variables. The differentiation in the form of aedeagus, however, was less significant than the differentiation of the shape and size of the wing. The relation obtained between the shape and size of the wings was divergent from the results found for other Drosophila species, presenting bigger and more rounded wings in the populations of South 1 latitude (PIR, AGU and RDI) and smaller and elongated wings in a population from the Northeast latitude range (CUR). The populations of Costa Rica (TIR and LSA) and the South population showed significant divergence for the markets evaluated, however, the populations of the Southeast latitudinal range (MAT, NGR, SDC, PIC and VIT) did not present congruent structures and were better grouped by phytophysiognomies. The present results reflect the genetic differentiation in course in D. Sturtevanti populations, being accentuated for those coming from Central America and those from Southern Brazil, indicating the occurrence of an differentiation in relation to markers studied and that may reflect the existence of new species of this subgroup, which had already been signaled in previous studies and in recent studies of our laboratory with molecular markers for these same populations.
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Palavras-chave
Diferenciação populacional, Plasticidade fenotípica, Cline latitudinal, Evolução morfológica, Especiação, Populational differentiation, Phenotypic plasticity, Latitudinal cline, Morphological evolution, Speciation